Reed Slap vs Vibration

[ben]

My thought are that for the call to make a sound the reed has to close the end of the tone channel on the slope and then the vibration of the reed there after is the sound with the reed constantly closing and opening the channel hole amplifying the reed vibration for the sound we hear.

ben

[Crawdad]

I don't have anything to say.

[dogcatcher]

I sent an email to an expert, he said we were nuts to wonder why but here is his response. 

http://hendrix2.uoregon.edu/~dlivelyb/phys152/l12.html

Reeds: The sound source in a reed instrument is fundamentally different than that of a flute. Air is blow past a reed causing it to vibrate. Your textbook points out that the frequencies at which the reed vibrates are "considerably higher" than the sound frequencies created by the entire instrument. Blowing on the reed initially causes it to close (Bernouli effect), and a compressed air packet travels down the instruments bore to the bell end. The reflected pulse is a rarefication of air (what does this say about the boundary conditions at the bell end?), which travels back up and reflects off the reed. The rarefication travels back down the bore (what does this tell us about the bounary condition at the reed end?) and again reflects and reverses at the bell. The resulting compressed air packet travels back up the bore and opens up the reed to complete the cycle. This raises questions in my mind regarding the assertion that the reed vibrates several cycles during the time of this 4-trip process of air compressions and rarefications traveling up and down the instrument tube.

Marvin

[Chris at Owens Custom Calls]

a simple 'yes it touches' or 'no, it doesn't' would have been too easy   

[Joe aka COLD @ J. A. Kolter Calls]

I don't have anything to say.

I have plenty to say, but I will let the believer's and non-believer's say what they want.   

[gooseforsupper]

Yep

[BLKDOGS]

Reeds: The sound source in a reed instrument is fundamentally different than that of a flute. Air is blow past a reed causing it to vibrate. Your textbook points out that the frequencies at which the reed vibrates are "considerably higher" than the sound frequencies created by the entire instrument. Blowing on the reed initially causes it to close (Bernouli effect), and a compressed air packet travels down the instruments bore to the bell end. The reflected pulse is a rarefication of air (what does this say about the boundary conditions at the bell end?), which travels back up and reflects off the reed. The rarefication travels back down the bore (what does this tell us about the bounary condition at the reed end?) and again reflects and reverses at the bell. The resulting compressed air packet travels back up the bore and opens up the reed to complete the cycle. This raises questions in my mind regarding the assertion that the reed vibrates several cycles during the time of this 4-trip process of air compressions and rarefications traveling up and down the instrument tube.

Marvin
[/quote]

So a reed instrument is like a 4 cycle internal combustion engine    I kind of get what was said here. 

Update on this project. we will be looking at this one day next week. I have got some parts in and have been running some tests on sound and air flow. I think I have what will work and will continue the Fab of the set up over the next 3 days. I do believe that we will see what the reed is doing. My camera operator is confedent we will be able to slow it down enough to see if it does touch or not. More next week.
 
 

[BigB]

Ron, this is going to get very interesting in a couple of days. Thanks again for all the work you are putting into this.

Brian

[Chris @ STW Outdoors]

Interesting stuff. This throws a small wrench in my theorizing. It is very good information and seems that it could be the case in a duck call. The camera should give us the whole story. I am still working on additional testing to go through the cadence and toneboard variations questions. I have the resource tracked down, not it is just a matter of scheduling and funding. Not sure on either of these. More to come.

[Andre's Wood Works aka: TheDecoyDude]

I'm pretty excited to see what happens! I salute the effort you are putting into this and wish for best ~Andre'

[wlain]

I am in the "Reed slaps the toneboard" camp.

[M. Miller]

I sent an email to an expert, he said we were nuts to wonder why but here is his response. 

http://hendrix2.uoregon.edu/~dlivelyb/phys152/l12.html

Reeds: The sound source in a reed instrument is fundamentally different than that of a flute. Air is blow past a reed causing it to vibrate. Your textbook points out that the frequencies at which the reed vibrates are "considerably higher" than the sound frequencies created by the entire instrument. Blowing on the reed initially causes it to close (Bernouli effect), and a compressed air packet travels down the instruments bore to the bell end. The reflected pulse is a rarefication of air (what does this say about the boundary conditions at the bell end?), which travels back up and reflects off the reed. The rarefication travels back down the bore (what does this tell us about the bounary condition at the reed end?) and again reflects and reverses at the bell. The resulting compressed air packet travels back up the bore and opens up the reed to complete the cycle. This raises questions in my mind regarding the assertion that the reed vibrates several cycles during the time of this 4-trip process of air compressions and rarefications traveling up and down the instrument tube.

Marvin

I am a music professor too and I don't find this to be a weird question or topic at all.The Bernoulli effect is produced, but some things need to be considered before one draws conclusion with operation.

 1. A reed in a duck call is manipulated and placed differently than that of a clarinet, saxophone bassoon or oboe. The reed found on these instruments is outside of the instrument chamber, a duck call reed is inside. Historically, there were capped reed instruments, and are to this day (bagpipes). It is capped reed instrument that hold more related character in operation than the modern reed instruments found in an orchestra.

2. The reed material and overall length of a duck call reed creates far more pliability than that of a reed found on a reed instrument. Although the reed is shaven down on a reed instrument, it is far shorter in length and not as flexible as Mylar.

3. The mouth of the duck caller does not support the sound production on a duck call (it doesn't create contact with the reed at any point). A reed player's embouchure needs to be precise to produce quality tones.  One could say the ligature found on a reed instrument acts the same the function of the cork notch.

It is how the reed freely moves in the duck call that make all this interesting to me.

[Lon @ First Flight Game Calls]

I am easily confused. I am curious as to how the results might help us make better calls? To quote Hillary, "At this point, what does it matter?". Not trying to start anything just wondering.

                                                   


          Lon

[Wade@WEBFoot]

My thought is, the more one knows about why and how something operates... the better they can manipulate it better it.
To me, if we find out the moving portion of the reed does or does  not contact the surface, that might help focus on the right area to achieve a specific sound or quality.   In addition what ever other info might be gleaned from seeing the reed in motion may prove to be as or even more useful.

I guess I look at it in terms of constant improvement.  Maybe it will help, maybe it will be a waste of time.  But should be interesting one way or another :D

Wade

[Longntooth]

I too am very anxious to hear the results of the filming. Over the years I have taught several folks how to use a duck call. I have always considered them to be a "musical" instrument with a reed in it. Not a reeded musical instrument, because there is a big difference as pointed out. The term "blow a duck call" should never be used, because you "blow a New Years EveWhistle". My point is that in order to get the sound we all are looking for, you don't "blow" air across the reed, you "force" air across the reed by pushing air from the diaphragm across the reed, causing it to vibrate and make that sweet sound of a hen Mallard with an acorn stuck in her throat, IMHO, and THIS is why I want to know if it slaps or not. Because as Wade says, it could give us info to improve the quality of our craft . Kitch